Chemical Education Today
Book & Media Reviews
Introduction to Macromolecular Crystallography by Alexander McPherson John Wiley & Sons: New York, 2002. 237 pp, ISBN 0471251224 (paperback). $73.50
Outline of Crystallography for Biologists by David M. Blow Oxford University Press: Oxford, UK, 2002. 236 pp, ISBN 0198510519 (paperback). $40 reviewed by Arthur Glasfeld
Fifteen years ago, when I first set foot in a crystallography lab, nearly every protein crystallographer had two crystallography textbooks on the shelf, X-Ray Structure Determination by Stout and Jensen (1), and Protein Crystallography by Blundell and Johnson (2). It is unlikely that many other practicing biochemists had either; macromolecular crystallography was a discipline apart. However, in the past decade, crystallography has had a dramatic impact on biochemistry, reshaping nearly every area of research. Ten years ago or so, books began to appear that were intended to satisfy a growing curiosity in how crystallography works. Perhaps the most successful of those was Crystallography Made Crystal Clear (CMCC) by Gale Rhodes of the University of Southern Maine, a book intended to provide the uninitiated with a solid—if not detailed—understanding of the practice and theory of macromolecular crystallography (3). Using analogy and a minimum of well-presented mathematics, Rhodes’s book provides the tools for anyone to read crystallographic literature with a critical eye, and, if they want, the ability to continue on to more specialized texts to truly master the technique. CMCC has been successful enough to launch a second edition (2000) and a terrific supporting Web site at http:// www.usm.maine.edu/~rhodes/CMCC/. I have often referred students to Rhodes’s materials and have used them myself while I have continued an irregular affiliation with X-ray crystallography. The two books reviewed here, Introduction to Macromolecular Crystallography (IMC) and Outline of Crystallography for Biologists (OCB) join CMCC as introductory guides to protein crystallography for non-specialists. The authors, Alexander McPherson of University of California, Irvine and David Blow of Imperial College, are professional crystallographers, both with substantial contributions to the field. While IMC is intended for beginning crystallographers and OCB for non-crystallographers, in truth they serve the same audience as CMCC—scientists with a non-physical bent interested in becoming familiar with X-ray crystallography as it is applied to biochemistry. Whether the reader continues onwards or remains content with the (considerable) level of
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understanding these books provide has little apparent impact on the presentation. In fact, both authors recognize that both audiences will be reading their books. McPherson’s Introduction to Macromolecular Crystallography grows out of a course he teaches each year at Cold Spring Harbor. His strengths as an educator are apparent from the first chapter. IMC benefits from strong writing and a gifted use of analogy to introduce the abstract issues associated with diffraction. I have no doubt that I’ll be using his descriptions to talk about crystallography with students in the future. Throughout, McPherson emphasizes the similarities inherent in the periodicity of macromolecular crystals and diffraction patterns, so that the reader can feel at least qualitatively comfortable with the relationship between electron density and the experimental data collected through X-ray diffraction. IMC is effectively the shortest of the three books mentioned here. By emphasizing description and illustration, its 230 pages provide somewhat less content than CMCC or OCB, despite the nearly identical lengths of those books. Broken into eight chapters, IMC emphasizes the basics of crystal packing and symmetry, wave phenomena, diffraction and structure solution. Chapters 2–4 form the core of the book, leading the reader through the nature of crystals, waves, and diffraction. McPherson takes his time here, and provides ample text to accompany the growing reliance on mathematics. Much of this is excellent, though Chapter 4, on diffraction, suffers from poor editing of figures and equations. Often multiple variables are used for the same physical measurement, and in one particularly troubling instance, a section on scattering relies on figures that consistently make an error in vector addition. The final three chapters, which deal with the phase problem and means of circumventing it, are less detailed and provide a good qualitative description of MAD, MIR, and molecular replacement methods yet give few details. Also, relatively little time is taken to describe methods of evaluating the quality of data and of the final model. IMC is not a good choice for the reader hoping to be able to interpret the tables of crystallographic data that accompany any new structure in the literature. I think more time could have been spent on those issues rather than the unusual emphasis on using precession photographs to investigate crystallographic symmetry. Chapter 5 contains 35 precession photographs, and eight other diffraction images. These images are not consistently identified with the method that produced them, and the precession method is only briefly described. In the end, it probably isn’t too important: few practicing crystallographers regularly use precession cameras these days. Symmetry is usually determined using automated software routines. Of course, problems can arise, and an understanding of the fundamentals can be critical. But in the end, the space used to present the various precession photos might have been better invested elsewhere. David Blow’s Outline of Crystallography for Biologists fills its 230 pages considerably more densely than IMC and is a
JChemEd.chem.wisc.edu • Vol. 80 No. 9 September 2003 • Journal of Chemical Education
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Chemical Education Today
Book & Media Reviews marvel. Chemists should beware of taking the title of this book too seriously. While Blow makes allowances for readers who are not mathematically inclined, he also makes a strong effort to appeal to those who are fundamentally curious about the mathematical background to the topic. While physical chemistry students may want a more rigorous treatment, I think many others will, like me, find this a satisfying treatment that provides a solid marriage between the mathematics and the concepts associated with diffraction and crystallography. Blow achieves this by providing boxes that set aside the mathematical derivations without affecting the flow of the text. OCB is also well illustrated, but Blow tends towards more conservative descriptions, writing cleanly, without the more descriptive style of the other two books. The result is impressive. Blow’s book does a masterful job of covering everything from X-ray generation to analyzing model quality. Obviously, given its length, OCB can’t provide details on any of these issues; still, there is enough here to allow the book to act as a reference for a developing or occasional crystallographer. Blow has divided the book in two sections, fundamentals and practice. The five chapters on fundamentals cover X-rays, crystals, and diffraction, and these chapters contain the bulk of the boxes in which the mathematics have been set aside. The writing is clear, the figures useful, and the equations are carefully presented throughout. The organization is similar to that of IMC, but the presentation is considerably more spare—these topics occupy only the first 100 pages of OCB but take 150 pages in IMC. Thus, Blow’s book has more space to devote to the process of collecting, processing, and interpreting data. These chapters are the particular strength of OCB. They provide an up-to-date, step-by-step description of practical crystallography. While OCB is not a “how to” manual, it does give the background necessary to understand what is being performed at each step and why. To augment the description, Blow makes frequent use of literature examples to illustrate the concepts. I’ve found that Blow’s descriptions are useful and his references are outstanding points of comparison. OCB provides individual
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chapters to discuss MIR, MAD, and molecular replacement methods, and each is presented with accessible language and technical accuracy. Where there is some current debate in methodology, Blow provides references to direct the reader. Outline of Crystallography for Biologists and Introduction to Macromolecular Crystallography effectively bracket Gale Rhodes’s Crystallography Made Crystal Clear in scope and technical detail. Each has strengths, and the reader interested in getting acquainted with macromolecular crystallography will benefit from having all three available. In my case, I will probably gauge student interest and sophistication in recommending one of the books. The first chapters of IMC are perfect for a novice without a strong background in mathematics, while CMCC is more comprehensive and includes more material (including a chapter on NMR methods). But for a more serious student, David Blow’s book is an exceptional choice. I have been recommending it to the graduate students and post-docs in my current sabbatical lab, and it should be considered as a textbook for an introductory course in crystallography. While Outline of Crystallography for Biologists lacks the depth of texts intended for specialists, it provides a thorough and accessible introduction and points the way to more detailed presentations. Literature Cited 1. Stout, George H.; Jensen, Lyle H. X-Ray Structure Determination: A Practical Guide, 2nd ed.; Wiley-Interscience: New York, 1989. 2. Blundell, T. L.; Johnson, L. N. Protein Crystallography; Academic Press: New York, 1976. 3. Rhodes, Gale. Crystallography Made Crystal Clear: A Guide for Users of Macromolecular Models, 2nd ed.; Academic Press: San Diego, 2000.
Arthur Glasfeld is in the Department of Chemistry, Reed College, 3203 S. E. Woodstock Boulevard, Portland, OR 972028199;
[email protected].
Journal of Chemical Education • Vol. 80 No. 9 September 2003 • JChemEd.chem.wisc.edu
